caramel apple cake

the goods:

applesauce:
3 fuji apples, peeled, cored, and quartered
3 golden delicious apples, peeled, cored, and quartered
1/4 cup apple cider
3/4 cup apple juice
2 tablespoons brandy
3 tablespoons butter
2 tablespoons honey
1 tablespoon dark brown sugar
3/4 teaspoon cinnamon

apple cake:
4 cups all-purpose flour
2 teaspoons baking soda
1 teaspoon baking powder
1 teaspoon salt
1 teaspoon cinnamon
1/2 teaspoon ground allspice
1/2 teaspoon ground cloves
1 and 1/2 cups (3 sticks) unsalted butter, cut into cubes, room temperature
2 and 1/2 cups sugar
2 large eggs
4 cups homemade apple sauce

caramel sauce:
1 and 1/2 cups sugar
1/4 cup light corn syrup
1/2 cup (1 stick) unsalted butter, cut into cubes, room temperature
1 and 1/2 cups heavy cream

caramel buttercream:
1 and 1/2 cups sugar
1/3 cup all-purpose flour
1 and 1/2 cups whole milk
1/3 cup heavy cream
1 and 1/2 cups (3 sticks) unsalted butter, cut into cubes, room temperature
1 teaspoon pure vanilla extract
1/3 cup plus 2 tablespoons caramel sauce

1 bag toffee bits

Homemade apple sauce: In a medium saucepan, combine apples, apple cider, apple juice, brandy, butter, honey, brown sugar, and cinnamon. Cover the saucepan and cook over medium heat for 15-to minutes, or until apples are soft. Allow to cool, then mash with a potato masher. Chill sauce to room temperature.
Apple cake: Preheat oven to 325 degrees. Butter three 8-inch cake rounds and line the bottoms with parchment paper, then butter parchment. dust with flour and knock out the excess flour. Whisk together the flour baking soda, baking powder, salt, cinnamon, allspice, and cloves in a medium bowl. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter until creamy, 4 minutes. Add the sugar and beat until light and fluffy, about 3 minutes. Add the egg and beat until combined. Add the flour mixture to the bowl in 3 parts, alternating with the applesauce (beginning and ending with flour). Scrape down the bowl, then mix on low speed for a few more seconds to combine. Divide batter among prepared pans and smooth tops. Bake for 40-45 minutes, rotating pans halfway through bake time, until toothpick inserted in the center of the cake comes out clean. Transfer pans to wire racks to cool for 20 minutes. Then turn cakes out onto racks, remove parchment, and cool completely.
Caramel sauce: In a medium saucepan, combine the sugar and corn syrup with 1/2 cup water. Stir the mixture gently, turn the heat up to medium-high and continue stirring until the sugar dissolves. Increase heat to high, stop stirring, and allow mixture to boil. Take caramel to 300 degrees on a candy thermometer, or until it turns a rich caramel color if you don't have a thermometer. Remove from heat and add butter and cream. Stir until combined. Cool to room temperature and store in a jar in the refrigerator until ready to use.
Caramel buttercream: In a medium saucepan, whisk the sugar and flour together. Add the milk and cream and cook over medium heat, whisking occasionally, until the mixture comes to a boil and has thickened, about 10-15 minutes. Transfer to the bowl of a standing mixer fitted with the paddle attachment. Beat on high speed until cool. Reduce speed to low and add butter and vanilla. Mix until thoroughly incorporated. Increase speed to medium-high and beat until the frosting is light and fluffy. Add 1/3 cup caramel sauce and continue mixing until combined.
Cake assembly: Place one of the cake layers on the cake base and level off the top (mine were already pretty level). Pipe a circular border around top edge of cake. Spoon a thin layer of caramel inside the border. then top with more buttercream to seal it in. Add another cake layer and level off top. Pipe another border of buttercream, fill with a thin layer of caramel and top with more buttercream. Add final cake layer, upside-down. Cover with a thin layer of buttercream all over entire cake (crumb coat) and place in the fridge to set, 30 minutes. Remove from fridge and finish frosting. Press toffee bits into side of cake on bottom half and top with caramel sauce on the top. Refrigerate until ready to serve.